This invention relates to hybrid laminated prepregs suitably used for the outermost layer of fiber reinforced composite resin material moldings, for instance such sport articles as golf club shafts, tennis rackets, ski pole shafts and fishing rods, fancy articles, briefcases such as attache cases, pipes such as bicycle frames and such panels as fair-faced wall panels to provide aesthetic appearance of these moldings. The invention also relates to fiber reinforced composite resin material ski pole shafts using the above hybrid laminated prepregs for the outermost layer of the shaft and having excellent aesthetic appearance.
Recently, fiber-reinforced composite resin material moldings, which are obtained by molding and hardening prepregs, i.e., fiber reinforced composite resins containing carbon fibers or like reinforcement fibers, are finding applications in various fields owing to their light weight and high mechanical strength. Fiber reinforced composite resin material moldings proposed and sold extensively include such sport articles as golf club shafts, tennis rackets, ski pole shafts and finishing rods, fancy articles, briefcases such as attache cases, pipes such as bicycle frames and such panels as fair-faced wall panels.
As such molding, a ski pole shaft comprises a plurality of fiber reinforced composite resin material layers. FIG. 8 shows such a structure. As shown, a predetermined number of fiber reinforced prepregs 101, cut to a predetermined shape and size, are wound on a mandrel 100, and the prepregs 101 are rendered to fiber reinforced composite resin materials by hardening the matrix resin, thus obtaining fiber reinforced composite resin material ski pole shaft. As will be understood more clearly with reference to FIG. 6 as well, to improve the twisting and bending performance the fiber reinforced prepregs include a prepreg 101S.sub.1 (straight layer 101S.sub.1 '), in which reinforcement fibers extend parallel (.theta.=0.degree.) to the axis of the ski pole shaft, prepregs 101A (101A.sub.1 and 101A.sub.2) (angle layers 101A'), in which reinforcement fibers are inclined at an angle (usually .theta.=25.degree. to 90.degree.) in opposite directions with respect to the axis of the ski pole shaft, and a prepreg 101S.sub.2 (straight layer 101S.sub.2 '), in which reinforcement fibers extend parallel (.theta.=0.degree. ) to the axis of the ski pole shaft. In many cases, the basic structure is as shown in FIG. 6, using the prepregs 101S.sub.1 and 101S.sub.2 (straight layers 101S.sub.1 ' and 101S.sub.2 ') as the innermost and outermost layers and the prepregs 101A (angle layers 101A') as the intermediate layers. Sometimes, the layers 101A (angle layers 101A') are omitted.
As shown in FIG. 7, the ski pole shaft may have a cylindrical structure having a uniform cross sectional size (FIG. 7(A) ) or a tapered structure (FIG. 7(B) ).
In the meantime, it is important that the fiber reinforced composite resin material moldings such as ski pole shafts, golf club shafts and tennis rackets as noted above have excellent aesthetic appearance. Usually, after a molding is obtained by winding, laminating and hardening prepregs on a mandrel, the aesthetic appearance is provided by polishing and coating. The operation of providing the aesthetic appearance, therefore, requires considerable man-hour. In addition, the decorated outer surface obtained by coating or the like lacks mechanical strength, and while the molding is used, break-away or wear of the coating layer of the decorated surface occur to spoil the aesthetic sense of the appearance.
For this reason, there is a demand for using a hybrid laminated prepreg with a decorative layer as the outermost layer in combination of usual prepreg in producing such fiber reinforced composite resin material moldings as ski pole shafts, golf club shafts and tennis rackets by using prepregs, thus permitting the aesthetic sense to be readily provided to the appearance of the molding, as well as dispensing with the time-consuming coating operation or the like and ensuring stable aesthetic appearance for long time. However, there has been proposed no such hybrid laminated prepreg, which has properties effective for readily meeting the above demand.